Project Summary E-cigarette or Electronic Nicotine Delivery System (ENDS) use has increased rapidly over the past decade, particularly among current cigarette smokers who often use ENDS to try to quit smoking. Whether ENDS help people quit smoking is largely unknown due to limited well-designed research in this area. While ENDS may or may not help people quit smoking, many people are entering smoking cessation treatment as dual users of cigarettes and ENDS. In fact, 40,000 dual users of cigarettes and ENDS call state tobacco quitlines for help quitting smoking each year. Treatment guidelines for addressing ENDS during smoking cessation treatment have been suggested, but have not been operationalized. That is, there are no empirically tested interventions for dual users of cigarettes and ENDS. The proposed study will address this gap by developing and testing an Enhanced ENDS Coaching (EEC) intervention for delivery through tobacco quitlines. This study has important public health significance and could lead to improved tobacco quitline services and tobacco cessation rates in the future. In addition, the developed treatment could be translated to other settings to improve services for dual users. The EEC Intervention will include education, shared decision making, and tailored behavioral support specific to dual users of cigarettes and ENDS. Individual differences in past cessation experiences, use experiences with ENDS and Nicotine Replacement Therapy (NRT), and knowledge gaps and incorrect beliefs about ENDS and NRT suggest that a patient-centered assessment and quit plan development approach plus enhanced ENDS-related behavioral support could increase smoking cessation success. Our primary goal is to improve smoking cessation rates among dual users and decrease rates of cigarette and ENDS dual use. We will educate dual users about the unknown long-term health impacts of ENDS, and encourage them to stop ENDS use when stopping will not precipitate a return to smoking. We hypothesize that, at 3-month follow-up (multimodal survey), EEC intervention participants will have similar or better program engagement and satisfaction, will rate their quit plan development experience more positively, and will report more accurate beliefs about ENDS, smoking and cessation medications, compared to dual users receiving quitline treatment as usual. We also will collect brief diary assessments on ENDS, cessation medication, and cigarette use to inform potential mechanisms for successful versus unsuccessful smoking cessation among dual users. During the two year project period, the investigators will develop the intervention and educational materials, train quitline counselors to deliver the intervention, refine the intervention with 10 dual users, and evaluate the feasibility and acceptability of the refined ECC by conducting a randomized pilot study with 100 dual users. Although this feasibility study is not powered to detect significant quit rate differences between groups, we will explore preliminary efficacy by examining the extent to which, at 3-months, the EEC increases smoking abstinence and decreases ENDS and cigarette dual use rates compared to treatment as usual.